Variscan amphibolite-facies rocks from the Kurtoğlu metamorphic complex (Gümüşhane area,Eastern Pontides,Turkey) |
| |
Authors: | Gültekin Topuz Rainer Altherr Winfried H Schwarz Abdurrahman Dokuz Hans-Peter Meyer |
| |
Institution: | 1.Avrasya Yerbilimleri Enstitüsü,Istanbul Teknik üniversitesi,Istanbul,Turkey;2.Mineralogisches Institut,Universit?t Heidelberg,Heidelberg,Germany;3.Gümü?hane Mühendislik Fakültesi, Jeoloji Mühendisli?i B?lümü,Karadeniz Teknik üniversitesi,Gümü?hane,Turkey |
| |
Abstract: | The Kurtoğlu metamorphic complex, that forms part of the pre-Liassic basement of the Sakarya zone in northern Turkey, consists
of at least two tectonic units. Blueschist-facies rocks of unknown metamorphic age in the southern part of the complex are
tectonically overlain by Variscan low-pressure high-temperature metamorphic rocks. The latter comprise mica schists and fine-grained
gneisses, cut by metaleucogranitic dikes, as well as migmatitic biotite gneisses and subordinate amphibolite intercalations.
Structural data indicate that metamorphism and penetrative deformation occurred after dyke intrusion. Peak metamorphic conditions
of the mica schists, fine-grained gneisses and metaleucogranites are estimated to ∼650°C and ∼0.4 GPa, based on phase relationships
in the system NCKFMASH, Fe–Mg partitioning between garnet and biotite as well as garnet-aluminosilicate-quartz-plagioclase
(GASP) and garnet-plagioclase-biotite-quartz (GBPQ) barometry. Peak temperatures of the migmatitic biotite gneisses and amphibolite
intercalations are not well constrained but might have been significantly higher (690–740°C), as suggested from hornblende-plagioclase
thermometry. 40Ar–39Ar incremental dating on muscovite and biotite fractions from the mica schists and fine-grained gneisses yielded plateau ages
of ∼323 Ma. Significantly older model ages of ∼329 and ∼337 Ma were obtained on muscovite fractions from two metaleucogranite
samples. These fractions contain both relict igneous and newly formed metamorphic muscovite. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|